package org.example.util;



import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

/**
 * @author kiki
 * @date 2023/2/28
 * @description
 */
public class AESUtil{


    /**将二进制转换成16进制
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }


    /**将16进制转换为二进制
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1){
            return null;
        }
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    /**
     * 加密
     * @param sSrc 需要加密的字符串
     * 此处使用AES-128-ECB加密模式，key需要为16位。
     * @return
     * @throws Exception
     */
    public static String Encrypt(String sSrc,String sKey) throws Exception {

        // 判断Key是否为16位
        if (sKey.length() != 16) {
            throw new Exception("Key长度不是16位");
        }
        byte[] raw = sKey.getBytes("utf-8");
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");//"算法/模式/补码方式"
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(sSrc.getBytes("utf-8"));
        return parseByte2HexStr(encrypted);
        //return new Base64().encodeToString(encrypted);//此处使用BASE64做转码功能，同时能起到2次加密的作用。
    }

    /**
     * 解密
     * @param sSrc 需要解密的字符串
     *  此处使用AES-128-ECB加密模式，key需要为16位。
     * @return
     * @throws Exception
     */
    public static String Decrypt(String sSrc,String sKey){
        byte[] sSrcc = parseHexStr2Byte(sSrc);
        try {
            // 判断Key是否正确
            if (sKey == null) {
                throw new Exception("Key为空null");
            }
            // 判断Key是否为16位
            if (sKey.length() != 16) {
                throw new Exception("Key长度不是16位");
            }
            byte[] raw = sKey.getBytes("utf-8");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            //byte[] encrypted1 = new Base64().decode(sSrcc);//先用base64解密
            try {
                byte[] original = cipher.doFinal(sSrcc);
                String originalString = new String(original,"utf-8");
                return originalString;
            } catch (Exception e) {
                System.out.println(e.toString());
                return null;
            }
        } catch (Exception ex) {
            System.out.println(ex.toString());
            return null;
        }
    }






}

